June 11, 1974
`"
`
`—F. E. AUZEL
`PREPARING FLUORESCENT MATERIALS FOR
`OPTICAL FREQUENCY CONVERSION
`Original Filed-Feb. 8, 1971
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`3,816,576
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`Fig. 7
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`VIZIO 1012
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`United States Patent 01 iice
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`3,816,576
`Patented June 11,, 1974
`
`1
`3,816,576
`PREPARING FLUORESCENT MATERIALS FOR
`OPTICAL FREQUENCY CONVERSION
`Francois E. Auzel, 39 Avenue Port-Royal des Champs,
`Le Mesnil-Saint-Denis, France
`Original application Feb. 8, 1971, Ser. No. 113,317, now
`Patent No. 3,709,827, dated Jan. 9, 1973. Divided
`and this application July 26, 1972, Ser. No. 275,435
`Int. ‘Cl. C04b 33/32
`.
`2 Claims
`
`US. Cl. 264-56
`
`ABSTRACT OF THE DISCLOSURE
`Fluorescent material for the optical frequency conver
`sion of near infrared radiation from 0.85 to 1.06 am. into
`visible radiation. The constituents of the material are (i)
`vitrifying ?uorides of lead, beryllium and magnesium, (ii)
`devitrifying and activating ?uoride of ytterbium and (iii)
`doping ?uoride of erbium for a green and red response
`and doping ?uoride of thulium for a blue response. The
`content of ytterbium ?uoride controls the form of the
`material, either glassy ceramic or polycristalline. Proper
`preparation conditions allow to prepare either a glass ma
`terial or a ceramic material.
`
`The present application is a division of applicant’s US.
`patent application Ser. No. 113,317, ?led Feb. 8, 1971,
`entitled, “Fluorescent Materials for Optical Frequency
`Conversion," now US. Pat. No. 3,709,827 granted Ian.
`9, 1973.
`The present invention generally concerns the materials
`for optical converters and, more particularly, for optical
`converters which permit the conversion of near-infrared
`radiation (ca. 0.85 to 1.06 am.) into visible radiation. The
`invention deals equally on one hand with the methods of
`producing these materials as well as the optical converters
`made therewith, and, on the other hand with certain ap
`plications thereof in devices which use them.
`Optical converter materials and optical converter
`screens made therewith are known from French Pat. No;
`1532609, ?led June 1, 1967, by the present applicant. This
`patent discloses two materials having the following com
`positions:
`'
`(a) A mixed tungstate of an alcaline metal and of
`ytterbium, lightly doped by a mixed tungstate of an alcaline
`metal and erbium, a composition which results in a green
`response material;
`(b) A mixed tungstate of an alcaline metal and of ytter
`bium, lightly doped by a mixed tungstate of an alcaline
`metal and of thulium, a composition which results in a
`blue response material.
`The same patent ‘gives quantitative formulas for the
`presented compositions, as well as their methods of prepa
`ration in powder form, and certain applications thereof
`for the manufacture of screens which function as optical
`converters, e.g. by packing these powders between two
`glass plates which must be smooth and parallel, or by
`settling these powders on any convenient support and hold
`ing them in place by the use of a coat of a synthetic trans
`parent resin.
`The physical and photoluminescent phenomena thus
`produced have been the subject matter of two papers given
`at the Paris Academy of Sciences, in 1966, tome 262, pp.
`1016 to 1019, and torne 263, pp. 819 to 821. The above
`cited patent presents a simple model of the phenomenon
`which consists of irradiating an ion-pair ytterbium-erbium
`or ytterbium-thulium in the near-infrared range.
`Other compositions in mono-crystal form are now
`known which differ from the ones above only by the host
`utilized. The principal ones are:
`(a) Simple lanthanum ?uoride (LaFa), gadolinium
`?uorides (GdFa), ytterium ?uorides (YF3) doped with
`
`2
`ytterbium (Yb3+) and as the case may be with erbium
`(Er3+) (for a green response) or with thulium (TMH)
`(for a blue response), or holmium (Ho3+) (for a red
`response);
`(b) Mixed barium and yttrium ?uorides (BaYlF5),
`mixed barium and lanthanum ?uorides (BaLaF5), doped
`with ytterbium and either erbium (for a green response),
`or thulium (for a blue response), or holmium (for a red
`response);
`(c) Yttrium oxy-chlorides (YOCl, YaOClq), doped with
`ytterbium and erbium (for green response).
`As regards these monocrystals which are drawn from a
`fusion-bath (a, b) or obtained through evaporation (c),
`pertinent references are as follows:
`(a) Hewes and Sarver, “Bulletin of the American Physi
`cal Society,” 1968, vol. 13, p. 687, and “Physical Review,”
`June 1969, vol. 182, p. 427;
`Kingley, Fenner and Galginaitis, “Applied Physics,"
`August 15, 1969, page 115;
`(b) Guggenheim and Johnson, “Applied Physics
`Letters,” June 15, 1969, pp- 51 and 52;
`(0) Van Uitert, Singh, Levinstein, Johnson and
`Orodkiewicz, “Applied Physics Letters,” June 15, 1969,
`pp. 53 and 54.
`By concentrating on the ions erbium (Er3+) and thuli~
`um (Tm3+), but by utilizing new hosts which will be
`speci?ed below, the applicant has obtained the following
`new results:
`Notably modifying the relative intensities of the radia
`tion emitted from the ion Er3+ as a result of different
`energy levels, i.e. the properties of the ion itself, thus per
`mitting the emission of at least one new color (green and
`red response instead of green response);
`Utilizing the capability of the new hosts mentioned to
`be produced in the different forms of glass, glassy ceram
`ics, or cristalline powders, hence permitting in?nitely more
`sophisticated methods of manufacture, less cumbersome
`than drawing out monocrystals. This results notably in
`ceramics with superior e?iciency for any given excitation
`power in comparison with mono-crystals and glass, and
`opens new devolopmental possibilities in the way of mixed
`glass-ceramic forms which will be discussed below.
`The principal object of the invention is to provide new
`solid ?uorescent materials for applications in optical con
`verters from near infrared radiation into visible radiation;
`another object of the invention is to provide methods of
`manufacturing said new infrared-visible converting ?uo
`rescent materials.
`According to this invention, the ?uorescent materials as
`well as the optical converters applying these materials and
`to be used for the conversion of the near-infrared band
`into visible radiation, are characterized in that they are
`made up of at least one of the following mixtures:
`(a) Mixture of ?uorides of lead, beryllium and magnesi
`um, having vitrifying properties, ytterbium ?uoride having
`devitrifying and activating properties and of erbium ?uo
`ride, a mixture which has a red and green response giving
`a yellow-orange color;
`(lb) Mixture of ?uorides of lead, beryllium and mag
`nesium, having vitrifying properties, ytterbium ?uoride,
`having devitrifying and activating properties and of thu
`lium ?uoride, a mixture which has a blue response;
`(c) Mixture of ?uorides of lead, beryllium and mag
`nesium, having vitrifying properties, ytterbium ?uoride
`having devitrifying and activating properties and of erbium
`and thulium ?uorides, a mixture that has a red, green
`and blue response.
`The ?uorescent materials of the invention can be ob~
`tained in the form of glass, of more or less glassy ceramics,
`and of cristalline powder by a proper selection of the
`ytterbium ?uoride content and the cooling conditions of
`the melted mixture.
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`The ?uorescent materials therefore include ?uorides of
`Similarly, it can be shown that the theoretical conver
`three kinds:
`sion efficiency is limited to 74% for the red light (ion
`Three ?uorides with vitrifying properties constituting
`Er“).
`the “body” of the material, no matter what the ?nal physi
`'Further e?iciency restrictions may result from the ab
`cal form of the material is going to be; these ?uorides
`sorption saturation of the ytterbium ion Yb3+ which is
`have been selected in such a way that the practical energy
`expected to occur for an infrared radiation power of
`e?iciency of the ?nal material be the best possible;
`several tens of kilowatts per cubic centimeter. As long as
`A devitrifying and activating ?uoride; it is said to be
`no such magnitudes of power are attained the conver
`devitrifying because its concentration enables the composi
`sion e?iciency can principally be increased, provided that
`tion to take the form of glass or ceramic on the one hand,
`the generated heat can be eliminated as quickly as it is
`or the powdery form on the other hand; it is said to be
`formed. In reality, however, the practical conversion
`activating because its presence is necessary for the optical
`efficiency limits are due to one or the other of the'two
`conversion by permitting coupling between the ytterbium
`causes mentioned above depending upon whether the
`ion Yb3+ and at least one other ion of a rare earth
`conversion process follows the quadratic or the cubic
`element;
`law.
`At least one doping ?uoride, namely that of erbium
`In the case of the green conversion an e?iciency of
`and (or) that of thulium, the corresponding rare earth
`7.10-5 was measured for a large band excitation power
`ions Br" and (or) Tm“!+ cooperating by coupling with
`density of 250 mw./cn1.3 which by way of a linear extra
`that of ytterbium in order to assure the conversion of
`polation (quadratic law) suggests for an irradiation limit
`infrared radiation into visible radiation the spectral com
`of 20 kw./cm.3 a practical maximal e?iciency of 56%,
`position of which will depend upon the nature of the
`an efficiency therefore that is below the theoretical value.
`doping ions.
`In the case of the blue emission an e?iciency of 3.10“?
`According to another aspect of the invention the
`was obtained for the same excitation power density of
`?nished compositions contain on one hand 20 to 45% by
`250 mw./cm.3 which by way of a quadratic extrapolation
`weight of lead ?uoride, 20 to 40% of beryllium ?uoride
`(cubic law) indicates an e?iciency of 68%, equal to the
`and 5 to 20% of magnesium ?uoride and less or more
`theoretical yield up to an excitation power density of 365
`than 20% of ytterbium ?uoride, depending upon whether
`w./cm.3 at which point saturation starts to occur.
`the solid form to be obtained is a glass or a more or less
`The method of preparing the ?uorescent materials of
`glassy ceramic on the one hand or a crystalline powder
`the invention and the optical converters including the
`on the other hand. Selection between a glass material or a
`same comprises the following steps:
`ceramic material depend upon the cooling conditions of
`(a) The vitrifying ?uorides are mixed ?rst in the cold
`the melted material.
`and as powders, then ytterbium ?uoride is added to this
`According to another aspect of the invention the com
`mix, followed by the addition of erbium and (or) thuliurn
`positions are such that the proportion of doping ?uorides
`?uoride and mixed;
`amounts to 1 to 4 atom-grams of erbium ?uoride and
`(b) The thus obtained mixture is heated to about
`(or) 0.25 to 1 atom-gram of thulium ?uoride per liter of
`1200° C. for about 6 minutes in a mu?le oven in order
`the ?nished material.
`to melt it;
`It can be demonstrated that at a macroscopic scale,
`(c) The product is allowed to cool slowly at room
`taking into account the statistical behaviour of all the
`temperature to about 500° C.;
`various ions, the radiation intensity IGR of the green and
`(d) The product is then given the desirable shape.
`red light (seen as a yellow-orange light) emitted by the
`The last step of the process can be varied in order to
`?uorescent material varies with the square of the incident
`obtain the desired form of the ?nished material:
`infrared radiation intensity 113 hence according to the
`(e1) Glass: the product is poured at 500° C. into a
`formula:
`mold with a jacket as a steel, uniformly heated to about
`100° C. and maintained there until the mixture has solid
`i?ed whereupon it is allow to cool further to room tem
`perature;
`(e2) Ceramic, more or less glassy; one proceeds as with
`the glass, but with one essential difference, the mold is
`uniformly preheated to 250° C. and is maintained at this
`temperature until the mixture has solidi?ed;
`(e3) Cake with a glass mantle and a ceramic center
`piece: again one proceeds as with the vglass, but one
`chooses a relatively deep mold, so that the liquid in con—
`tact with the mold wall will vitrify whereas the center
`portion will transform into ceramic;
`(e4) Crystalline powder: the last step of the general
`process is simpli?ed to the point that the product is left
`to cool to room temperature in the fusion crucible itself
`and it is then treated so it can serve at least for one
`of the methods of a group that comprises (a) packing be
`tween two thin smooth parallel, transparent glass plates,
`(b) sedimentation and coating by a transparent, synthetic
`resin, (c) suspension in a transparent gel; in this instance
`there is no vitri?cation, not even partial vitri?cation;
`(e5) Cake with a glass coating which is lenticular on
`one side and with a ceramic body inside. The glass lenses
`can be utilized to concentrate the infrared excitation radia
`tion. One proceeds as with the previous cake (e3) using
`a honeycomb mold instead. Taking into account the re
`fraction index of the ?nished glass of the order of 1.37
`and the calculated distance of the infrared source of radia
`tion, the honeycomb cavities will have the desired curva~
`ture radius in order for the radiation to focus in the inner
`bordering ceramic behind the lenses.
`
`'IIR<AGR/AB
`and the opposite is true, i.e. the blue light is more inten
`sive than the yellow-orange light, when the intensity of
`the infrared beam is such that
`IIR>AGR/AB
`Therefore, the resulting light color depends upon the
`excitation power.
`The theoretical conversion e?iciency, i.e. the ratio of
`emitted visible radiation power to infrared radiation power
`is limited by the production of phonons to:
`90% for the green light (ion Er“)
`68% for the blue light (ion Tma'l')
`
`IGR=AGRIIR2
`whereby AGR is a constant which at constant tempera
`ture depends only upon the dope concentration, and the
`radiation intensity 1;; of the emitted blue light varies with
`the cube of the incident infrared intensity Im, hence ac
`cording to the formula:
`I13: ABIIR3
`whereby AB is a constant which at constant temperature
`depends only upon the proportion of the dope.
`For a mixed material responding simultaneously to
`infrared irradiation with yellow-orange and with blue
`light, one can write:
`
`indicating that the yellow-orange light is more intensive
`than the blue light when the intensity of the infrared beam
`is such that:
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`3,816,576
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`5
`The invention will be more easily understood by read
`The optical converters according to this invention are
`ing the detailed description below of several embodiments
`parts that are apt to be used in numerous optical systems,
`together with the accompanying drawings in which:
`such as, among others:
`FIGS. 1 to 3 are views in perspective of partially cut
`Luminous marks for illumination or for signalling, for
`molds which are used to cast optical converters which
`instance in telephone switchboards, automobile and air
`respectively have the shape of glass plates with parallel
`plane dashboards, instrument panels of satellites, data
`faces, lenses, screens with a lenticular face of glass and
`visualization consoles for calculators;
`an inner ceramic body;
`Screens for the detection of infra-red radiation;
`FIG. 4 represents a cut through a screen in accordance
`Low de?nition television receivers with ?at screens.
`with the invention as it was produced by means of the
`As already discussed, the conversion e?iciency increases
`mold in FIG. 3; and
`with the infra-red radiation intensity which irradiates an
`FIG. 5 represents a schematic view of a cut through a
`optical converter. There 'is therefore an inducement to
`luminous mark in accordance with the invention, involv
`spectrally concentrate said irradiation.
`ing an infrared source, an optical converter of ceramic
`A photodiode with an emission band as narrow as pos
`material and an optical ?lter.
`sible, centered upon a wavelength close to 0.97 ,um must
`be selected since the value of the wavelength of optimal
`sensibility depends largely upon the ytterbium ion’s
`(Yb3+) own properties and the maximal excitation of the
`optical converters of the invention is obtained with a radi
`ation of 0.97 am. wavelength. Nevertheless a satisfactory
`excitation can be obtained by a radiation of wavelength
`of between 0.92 and 1 ,um. Thus, the classical diodes of
`the gallium arsenide type are not convenient as excitation
`sources since their radiation has a wavelength of 090 ,um.
`It is possible though to use gallium arsenide diodes doped
`with silicium, since the radiation it emits has a wavelength
`that falls within the lower bracket of the range mentioned
`above. For instance, it is possible to use:
`the photodiode PEX 1206 of the Texas Instrument Corp.
`(0.93 am)
`the photodiode SSL 15 of the General Electric Corp.
`(0.94 am)
`But it is still preferable for the sake of the optical con
`verters of this invention to make diodes the radiation of
`which centers upon the wavelenth of 0.97 ,urn.
`It is now known that the wavelength of the radiation
`emitted by the semiconductor diodes made up of alloys
`of ternary compounds of III-V elements (III and V desig
`nate the groups in the periodic table of the elements)
`can be varied simply by varying the relative composition
`of each alloy. The energy gap of the alloy varies substan
`tially linearly with its mole composition between the
`energy gaps of its individual constituents.
`Alloys which are convenient for making diodes whose
`radiation centers reasonably close upon the 0.97 ,um.
`wavelength are:
`(1°)——the indium-phosphor-arsenic alloy of the formula
`
`Grams
`Beryllium ?uoride in form of a mixture of ammo
`nium ?uoride and ‘beryllium ?uoride NH4BeF4 __ 3,633
`Magnesium ?uoride _______________________ __ 0,683
`Lead ?uoride _____________________________ __ 9,8018
`Ytterbium ?uoride ________________________ ___ 4,598
`Erbium ?uoride ____________________________ __ 1,192
`EXAMPLE NO. 2
`Fluorescent material with a blue response
`Composition of the material:
`
`Grams
`Beryllium ?uoride in form of a mixture of ammo
`nium ?uoride and beryllium ?uoride NH4BeF4 _ 3,633
`Magnesium ?uoride _______________________ __ 0,683
`Lead ?uoride _____________________________ __ 9,808
`Ytterbium ?uoride ________________________ __ 4,598
`Thuliumfluoride __________________________ __ 0,149
`EXAMPLE NO. 3
`Fluorescent material with a red, green and blue response
`Composition of the material:
`
`Grams
`Beryllium ?uoride in form of a mixture of ammo
`nium ?uoride and beryllium ?uoride NH4BeF4 _ 3,633
`Magnesium ?uoride _______________________ __ 0,683
`Lead ?uoride _____________________________ __ 9,808
`Ytterbium ?uoride ________________________ __ 4,598
`Erbium ?uoride __________________________ _... 1,192
`Thulium ?uoride __________________________ __ 0,149
`We now refer to FIGS. 1 through 3 which give examples
`of molds that can be used to cast the mixtures for form
`ing the optical converters.
`"
`Mold 1 of FIG. 1 is formed with rectangular cells
`11-13; however, these sections might as Well assume other
`geometric shapes; here, the rectangular section permits
`the casting of the plates with parallel faces of glass or
`ceramic. Mold 2 of FIG. 2 is formed with cavities 2143
`in form of a portion of a sphere which are used to pro
`duce glass plane-convex lenses; the curvature radius of
`the cavities and hence of the convex faces of the lenses
`determines the convergence-value of the lenses, taking
`into account that the refractive index of the ?nished glass
`product is of the order of 1.37.
`The mold 3 of the FIG. 3 has cavities 31—33, which are
`analogous to those of the mold in FIG. 2, but it is deeper
`and is intended to be used for the production of a “mixed
`cake” 4 (see FIG. 4) having an inner ceramic body 40
`enrobed in glass, whereby the glass envelop has on one
`of its faces an array of regularly distributed lenses 41-48.
`Again taking into account the refractive index of the
`?nished glass of about 1.37 and the anticipated position
`of the infrared source on the axis of each lens, the curva
`ture radius of the mold cavities and hence of the ?nished
`
`EXAMPLE NO. 1
`
`Fluorescent material with a green and red response
`Composition of the material:
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`In (PXAs1_x)
`
`where 0.98<x<1
`On this subject one can refer to the paper of F. B.
`Alexander, “Applied Physics Letters,” tome 4, 1964, p. 13.
`(2°)-—the arsenic-indium-gallium alloy of the formula
`As (InxGa1_x)
`where 0.005 <x<0.15
`On this subject one can refer to the paper by I. Mel
`engailis, A. I. Strauss, R. H. Rediker, “Proceeding of the
`I.E.E.E.,” August 1963, p. 1154.
`(3°)—The antimony-aluminum-gallium alloy of the for
`mula
`
`Sb (AlxGa1_x)
`where 0.37<x<0.74
`On this subject one can refer to the paper by I. I. Bardi
`yan, “Fizika Tverdogo Tela,” vol. 1, No. 9, Moscow, Sep
`tember 1959, p. 1360.
`Since a semi-conductor diode can attain a luminous e?i
`ciency of 10% the optical converters of this invention
`asymptotically permit the attainment of a total electro
`luminous e?iciency of 5 to 7%.
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`the gel can contain a suitable dye permitting it to play the
`lenses of the cake can be so chosen as to allow focussing
`of the infrared irradiation in the subjacent ceramic
`role of optical ?lter.
`layer 40.
`For the sake of the appended claims, it is to be noticed
`FIG. 5 relates to a luminous mark for signal boards.
`that a concentration of x atom-grams per liter correspond
`It essentially comprises a solid state source of infrared
`to a concentration of x><N/103 par cm.3 where N is the
`radiation, preferably, a photodiode of the infrared semi
`Avogadro’s number équal to 6X10”.
`conductor type, and an optical transformer in accordance
`What I claim is:
`with the invention.
`1. A method for preparing ?uorescent material for
`More precisely, a photodiode 11 is placed on a metallic
`optical conversion of near infrared from 0.85 to 1.06
`base 12 with two terminals 13 and 15. The photodiode is
`millimicrons into visible radiation comprising the steps
`soldered onto the base. A gold wire 14 is attached to the
`of
`upper surface of the diode and to terminal 15 and is iso
`(a) mixing at room temperature ?nely divided solid
`lated from base 12 by means of a glass pearl 16. The
`?uorides of lead, magnesium, berryllium, as vitrifying
`diode 11 and its base 12 are covered by a metallic hood
`agents with ytterbium ?uoride, which has devitrifying
`17. The top of the hood 17 consists of an optical con
`properties and with a powdered doping agent selected
`verter in accordance with the invention, in this case, a
`from the group consisting of erbium fluoride for
`ceramic plate with parallel faces 18. A metallic lid 19
`red and green at a concentration of 6x1020 to
`whose bottom has a circular opening 19a ‘?ts into the
`24x1020 atoms per cm.3 and thulium ?uoride at a
`upper end of the hood 17. This lid holds an optical ?lter
`concentration of 1.5 x 1020 to 6x1020 atoms per cm.3
`20 known in the prior art in case it should be required.
`for blue, the weight percentages being
`Such a luminous mark can emit visible light of 'five differ
`lead ?uoride: 20-35%
`ent colors:
`beryllium ?uoride: 20-40%
`magnesium ?uoride: 5—20%
`ytterbium ?uoride: balance to 100%
`except for doping amounts,
`(b) heating the mixture to about 1200° C. in a
`crucible, the mixture containing a su?icient amount
`of devitrifying ?uoride to prevent glass formation,
`and
`(c) cooling the powder mixture from the heating step
`in (b) to room temperature whereby a powdered
`product is obtained adapted to be formed as an elec
`troluminescent self-supporting layer when dispersed
`in a binder.
`2. A method as claimed in claim 1 wherein said
`powder is packed between parallel transparent glass
`plates to provide an electro~luminescent converter of
`rectangular shape.
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`1.—glue: plate 18 thulium-doped, only; no filter 20
`2.—green: plate 18 erbium-doped, only; ?lter 20 green
`3.—yellow-orange: plate 18 erbium-doped, only; no ?lter
`20
`4.—red: plate 18 erbium-doped, only; ?lter 20 red
`5.--white or blue
`plate 18 erbium and thulium-doped
`or
`depending upon intensity; no
`yellow/orange
`?lter 20
`
`Several changes can be made in the structure of the
`luminous mark of ‘FIG. 5:
`1.—-The homogeneous plate 18 can be replaced by a
`plate of the mixed glass-ceramic type (of FIG. 4) with
`plano-convex glass lenses facing the diode; the luminosity
`of such a mark will be notably increased for reasons
`already discussed;
`2.—-While using a homogeneous ceramic plate 18 with
`parallel faces the diode 11 can be replaced by a prior art
`diode, a so-called dome-diode, such as the PEX 1206 of
`the Texas Instrument Corp.; this diode has its own source
`of radiation in the center of a portion of sphere of trans
`parent semiconductor material; by giving the hood con~
`venient dimensions, the infrared radiation emitted by the
`diode can be focussed in the plate 18.
`3.-—The interior of the hood 17 can be ?lled entirely
`with a translucid silicone gel which opens up two pos
`sibilities:
`the gel can contain grains of a crystalline powder accord
`ing to the invention in suspension and thus play the role
`of an optical converter;
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`References Cited
`UNITED STATES PATENTS
`3,541,018 11/1970 Hewes et a1. ____ 252-301.4 H
`3,203,899
`8/1965 Fisher ______ ___ 252-3014 H
`3,533,956 10/1970 Snitzer ______ __ 252—301.4 R
`3,667,921
`6/1972 Grodkiewicz et a1.
`
`3,649,552
`3,709,827
`
`252--301.4 H
`3/1972 Robinson ____ __ 252—30l.4 H
`1/1973 Auzel ___________ _._ 106—47 R
`
`DONALD J. ARNOLD, Primary Examiner
`
`US. Cl. X.R.
`106—47 R; 252—301.4 R; 264-—332
`
`VIZIO 1012